This invention relates to a plunger operating mechanism for operating a parison plunger in an I.S. type glassware forming machine.
In the production of glass containers by the press and blow method on the well known I.S. type machine, a gob of glass is provided to a parison mould, which is then closed, and the glass is pressed into the required shape of a parison by a plunger moving upwardly into the mould, a lower portion of the glass being forced into a neck ring of the parison mould. The plunger is then withdrawn and the parison is carried by the neck ring away from the parison moulding station, and is transferred to a blow mould station at which it is blown into the required shape.
Known plunger mechanisms incorporate a powerful spring, and movement of the plunger into its lower most position, in which it is out of the way of the parison to allow the parison to be moved from the parison moulding station, requires compression of this spring. When the mechanism has to be adjusted, on change of the parison mould, it is necessary to remove a spacer from inside the mechanism and replace it, which can be difficult. Further, on disassembly of the mechanism it is necessary to release the spring in the mechanism which is an awkward and somewhat dangerous operation necessitating the use of a special tool.
It is an object of the present invention to provide a plunger operating mechanism which may be more easily adjusted.